Final answer:
The correct form of the verb is 'recibes' to match the subject 'tú' (you).
Step-by-step explanation:
The correct form of the verb to complete the sentence is recibes.
When asking the question ¿Tú notas buenas en la clase de matemáticas? (Do you get good grades in the math class?), the subject 'tú' (you) requires the corresponding verb form 'recibes' (you receive).
For example, if we use the subject 'él' (he), the correct verb form would be 'recibe' (he receives).
Learn more about Verb forms in Spanish